Twisted ether-free polymer based alkaline membrane for high-performance water electrolysis

Abstract To prepare high-performance anion exchange membrane, a twisted ether-free polyarylene piperidinium (QMter-co-Mpi) has been successfully synthesized via simple and controllable acid-catalyzed polycondensation reaction for alkaline water electrolysis. The hydroxide conductivity of QMter-co-Mpi membrane reaches 37 mS cm−1 at 30 °C owing to the fact that an efficient ion-conducting channels are formed by means of this unique molecular structure. Furthermore, the IEC and hydroxide conductivity of the membrane can remain above 80% of the original values after alkali treatment for more than 1000 h, indicating exceptional alkaline stability. As a result, the QMter-co-Mpi based cell presents a high current density of 1064 mA cm−2 at 2.5 V under 1 M KOH and 50 °C and the high frequency resistance of the cell is only 0.165 Ω cm−2 at 1.8 V. The durability test is performed at current density of 200 mA cm−2 for more than 500 h and the voltage is basically remained at 2.1 V, showing excellent electrochemical performance. All these demonstrate a good application prospect for QMter-co-Mpi membrane in water electrolysis.